My invention pertains to a method for reducing the concentration of oxides of nitrogen (NOx) formed in fossil fuels combustion and combustion effluents. In one aspect my invention relates, to the admixture of hydrazine [N.sub.2 H.sub.4 ] and/or hydrazine compounds, such as Dimethylhydrazine [(CH.sub.3).sub.2 N.sub.2 H.sub.2 ] and Unsymmetrical Dimethylhydrazine (i.e. UDMH), to liquid fossil fuels for the reduction of the oxides of nitrogen produced in combustion of liquid fossil fuels such as gasolines and fuel oils, used in internal combustion engines, diesel engines, gas turbines, process furnaces, power plant boilers and other combustion equipment. In another aspect, my invention relates to the injection of hydrazine and/or Hydrazine compounds such as hydrazine hydrate [N.sub.2 H.sub.4.H.sub.2 O], Dimethylhydrazine and UDMH, into the fossil fuels main combustion zone for reduction of the oxides of nitrogen produced in the combustion of solid, liquid and gaseous fossil fuels and subsequently in the discharged combustion effluents from fossil fuels fired combustion apparatus and devices, including but not limited to gas turbines, power plant boilers, process furnaces, fired heaters, steam boilers.
Fossil fuels combustion waste products discharged from various combustion sources into ambient atmosphere have become a major cause of harmful air pollution resulting in serious smog problems. The major health irritants in smog are the oxides of nitrogen (NOx) amongst which nitrogen dioxide (NO.sub.2) being extremely poisonous gas presents the most serious problem. Major portion of the NOx discharged into the atmosphere comes from fossil fuels combustion in automotive internal combustion engines, but stationary sources of NOx discharge such as power plants, fired boilers and process furnaces, incinerators and similar combustion equipment are also significant contributors. In these combustion processes thermal NOx is formed as nitric oxide (NO) in the high temperature combustion zone from the nitrogen and oxygen in the combustion air and of the combustion gases. The high temperatures in the combustion zone favour NO formation, the original form in which the oxides of nitrogen are created in the combustion process. This NO is subsequently oxidized to NO.sub.2 as soon as the lower temperature required for this are reached in zones of great local air oxygen surplus and upon discharge into ambient air. In addition to the formation of NO, from nitrogen and oxygen available in the combustion air as "thermal NOx", the combustion of fuels containing organically bonded nitrogen will eventually form the so called "fuel NOx".
In prior art there have been considerable and numerous efforts to find an effective method of removing NO and NO.sub.2 from combustion effluents by catalytic reduction alone and with the injection of ammonia into the combustion effluents as the reducing agent. The prior art relates to NOx reduction methods constrained to NO reduction in the combustion gases effluent flow downstream of the region of fuel combustion where the effluent gases have cooled down to the lower temperature range required by the catalyst to promote an effective catalytic reaction, without exposing the catalyst to unacceptable thermal degradation damage or destruction. A notable exception to the method of NOx reduction in the combustion effluent stream is the use of demineralized water or steam injection into the fuel combustion zone of stationary gas turbines to supress NO formation in the fuel combustion zone by decreasing the combustion zone flame temperatures.